Safeguard device for automotive electrical systems



Feb. 13, 1962 N. STARCK 3,021,429

SAFEGUARD DEVICE FOR AUTOMOTIVE ELECTRICAL SYSTEMS Original Filed Dec.4, 1953 NOEL L. STARCK,

A T TORNEV.

tery by the engine starter.

3,021,429 SAFEGUARD DEVICE FOR AUTOMOTIVE ELECTRICAL SYSTEMS Noel L.Starck, 6526 West Blvd., Los Angeles, Calif. Substituted for abandonedapplication Ser. No.-396,239, Dec. 4, 1953. This application Dec. 28,1960, Ser.

7 Claims. (Cl. 30710) This invention relates to an electrical circuitfor an in-,

application 396,239, which recovers verbatim the seven,

claims that were filed December 4, 1953, and allowed July 25, 1956,entitled Safeguard Device for Automotive Electrical Systems, that wereabandoned under the Law (35 U.S.C. 151) and which Patent 2,904,702 is adivision thereof. 7 g

One advantage of such an arrangement is, of course, the elimination offire hazard, and especiallywhen the vehicle is parked and unattended. Asecond advantage.

is the prevention of damage to the components of the wiring system thatmay arise from short circuiting or overloading. A third advantage isconservation of the battery itself as well as safeguard against runningdown the battery.

A fourth advantage is that the invention discourages car theftespecially when the invention is installed on an automobile having alocked hood. A car thief cannot use a jumper wire to shunt the ignitionkey at the dash because all of the circuitry at the dash isde-energized. Such a jumper wire can be installed successfully only ifaccess is gained to the present invention which is installed under thehood of the car.

In general these advantages are provided by an electrical automotivecircuit in which at least one side of the battery is completely isolatedor disconnected when the ignition switch is open and in which currentflow through the circuit under direct control of the ignition switch isheld to a minimum. Thus, when the key for United States Patent theignition switch is withdrawn, no circuits whatsoever can be closedthrough thestorage battery of the vehicle and when the ignition key isinserted to close the ignitionswitch, the result is merely relativelylight current flow through a limited portion of the wiring system.

A feature of the preferred practice of the invention is the use of abattery-isolated relay having two coils to provide twoditferentmagnitudes of contact-closing force. One of these 'two coils ofthe relay is a main coil that is employed for normal energization of theelectrical system by the storage battery. The other of the two coils isan auxiliary coil or supplemental coil which may be aptly'terrned abooster coil since it provides added contact-closing force. The solefunction of the ignition switch of the automotive wiring circuit is toenergize the main coil for a minimum level of current flow from thebattery, the current being sufiicient to close the relay with relativelylight contact-to-contact pressure. Since the contacts of this relay inthe one practice of theinvention provide the only connection between oneside of the battery and the rest of the wiring system, the contactsmust, on occasion, carry peak load imposedon the storage bat- Thestarter switch is connected to the relay contacts and provision is madefor energizing the second or booster coil of the relay in response toenergization of the engine starter. Thus, the

ice

starter circuit cannot be closed unless the ignition switch is firstclosed and. the booster coil is automatically energized to increase thecontact-to-contact pressure of the relay whenever the demand arises forpeak current flow through the engine starter circuit. In this way, onecircuit arrangement of the. present invention makes it possible to use aminimum level of current flow to connect the battery with the rest ofthe circuit and to hold the battery connection closed during normaloperation of the engine. At the same time the circuit arrangementprovides for additional flow of current to energize the relay whenrequired to prevent overheating, burning and pitting of the relaycontacts.

One practice of the invention is further characterized by the provision,as a new article of manufacture, of a simple unit that may be added toany automotive electrical system to convert the wiring system of thevehicle to the new mode of safety operation. A feature of the inventionin this regard is that the accessory unit may be installed in a simplemanner requiring no special technical skill or knowledge.

The various features and advantages of the invention will be apparent inthe following detailed description considered with the accompanyingdrawing.

In the drawing, which is to be regarded as merely illustrative:

FIGURE 1 is a schematic wiring diagram embodying one form of theinvention;

FIGURE 2 is a similar diagram of a second form the invention; and

FIGURE 3 is a similar diagram of a third form of the invention.

FIGURE 1 shows some of the essential components of a conventionalautomotive electrical system including a storage battery 10, an ignitionswitch 11, an engine starter indicated by the broken line rectangle 12,a starter switch 13 and an ammeter 14.

The engine starter 12 includes the usual starter relay,

represented by the inner solid line rectangle 18, which is.

22 and 23. .One side of the relay coil 20 is grounded asindicated in 25and the other side is connected by a wire 26.to one side of the starterswitch 13.

The positive side of the battery 10 is connected by a wire 30 with thestationary contact 23 of the starter relay 18 and this stationarycontact is connected by a wire 31 to one side of the ammeter 14. Thesame side of the ammeter 14 is connected by a wire 32 to the second sideof the starter switch 13 and is connected by a wire 33 with one side ofthe ignition switch 11. The other side of the ammeter 14 has at leastone wire 34 connected thereto in the usual manner to serve as anaccessory power supply conductor for energizing various componentsincluding the components of the lighting system of the automobile. Amongthe components energized by the power supply conductor 34 are the sparkplugs of the engine. The ignition circuit which energizes said sparkplugs is connected directly to wire 34, and therefore its efiectiveenergization is controlled by the contacts 43, 44, 45, which areclosedby the energization of the main relay, coil 40 (FIGURES 1 and 2) or ofthe relay coil (FIGURE .3) by the ignition switch 11, as will be.

al in an automotive electrical system and, of course, a typicalautomotive wiring circuit includes additional components which need notbe described for the purpose of the present disclosure.

While the principles of the invention may be incorporated in anautomotive wiring system in various ways in various practices of theinvention, preferably the necessary components for converting aconventional wiring system into the new safety system are provided by asingle unit having a housing or casing represented by the solid linerectangle 37. As will be apparent such a unit may be manufactured andsold as an accessory device to be installed in a conventional automotivewiring system.

The housing 37 of the new unit encloses a main relay coil 49, anauxiliary booster relay coil 41 and a relay armature 42 that is commonto and responsive to both of these coils. The armature 42 carries amovable contact 43 to bridge or interconnect a pair of stationarycontacts 44 and 45. A suitable spring 46 urges the movable contact 43 tothe open position shown in FIGURE 1 and energization of either of thetwo coils 4t) and 41 moves the contact 43 to closed position inopposition to the spring 46.

The stationary contact 44 is integral with a terminal 47 on the exteriorof the unit casing 37 for connection with the negative side of thebattery by a wire 48. In like manner, the stationary contact 45 insidethe unit is integral with an exterior terminal 49 for connection by awire 50 to ground as indicated in the drawing.

One end of the main relay coil 40 of the unit is connected to thestationary contact 44, preferably through a suitable resistor 54 thatlimits the amount of current flow through the coil but neverthelesspermits sulficient current flow to overcome the resistance of the spring46. The other side of the main relay coil 49 is connected to an externalterminal 55 of the unit for connection by a wire 56 to the second sideof the ignition switch 11. One side of the booster relay coil 41 isconnected to the stationary contact 45 and the other side is connectedto an external terminal 57 of the unit for connection by a wire 58 withthe stationary contact 22 of the starter relay 18. This stationarycontact 22 of the starter relay is connected in the usual manner to thestarter motor by a wire 59, the other side of the starter motor beinggrounded to complete the starter circuit.

When the ignition switch 11 is closed, the following circuit iscompleted to energize the main relay coil 40; the positive side of thebattery 10; wire 30; wire 31; wire 33, ignition switch 11; wire 56;terminal 55 of the safety unit; coil 46'; resistor 54; terminal 47 onthe exterior of the unit; and wire 48 to the negative side of thebattery.

Energization of the main relay coil 40 by closing of the ignition switch11 actuates the armature 42 to make it possible for the starter switch13 to energize the starter relay 18. When the starter switch 13 is thenclosed While the ignition switch 11 is closed, the following circuit iscompleted through the coil of the starter relay 18: the positive side ofthe battery 10; wire 30; wire 31; wire 32; starter switch 13; wire 26;starter relay coil 20; ground Wire 50 from ground to the externalterminal 49 of the unit; contact 45 inside the unit; movable contact 43;contact 44; external terminal 47; and wire 48 to the negative side ofthe battery.

The closing of the movable contact 21 against the two stationarycontacts 22 and 23 resulting from energization of the coil 20 of thestarter relay 18 completes the following circuit for energization of thebooster relay coil 41 in the unit casing 37; positive side of thebattery 10; wire 30, stationary contact 23 in the starter relay 18;movable contact 21; stationary contact 22; wire 58; terminal 57 of theunit; booster relay coil 41; contact 45; movable contact 43; contact 44;external terminal 47; and Wire 48 to the negative side of the battery.

From the foregoing, it is apparent that when the ignition switch 11 isopen, the negative side of the battery 10 is isolated or disconnected toprevent any current flow whatsoever throughout the wiring system, andthat when the ignition switch 11 is closed, only such relatively weakcurrent will flow as will be necessary to energize the main relay coil40 for holding the movable contact 43 lightly against the two stationarycont-acts 44 and 45 inside the unit. It is further apparent that whenthe starter switch 13 is closed to draw a peak load of current from thebattery 10 for energizing the engine starter, the booster relay coil 41will be automatically energized at the same time to increase thepressure of the movable contact 43 against the two stationary contacts44 and 45 for more effective cooperation of the contacts to avoidoverheating, burning and pitting of the contact surfaces.

It will be readily appreciated that it is a simple matter to install thenew unit in a conventional automotive wiring system. In this instance,prior to installation of the unit, the negative side of the battery 10is grounded and it is merely necessary to interpose the unit between thebattery and ground. Thus, the unit casing 37 is mounted in a convenientlocation for connection of the unit terminal 47 to the battery and theunit terminal 49 to the ground. The other wires of the system arerearranged for the proper connection with the two unit terminals 55 and57, the ignition switch being connected to one terminal and the starterswitch being connected to the other.

The wiring diagram of the second embodiment of the invention shown inFIGURE 2 is largely identical with the wiring diagram shown in FIGURE 1,as indicated by the use of corresponding numerals to designate identicalparts. In this instance, the unit, which has a casing 61, is installedin an automotive wiring system in which the storage battery 60 has itspositive side grounded as indicated at 63, and the external terminal 47of the unit is connected to the negative side of the battery by the wire48. The particular embodiment of the unit employed in this arrangementhas a fifth external terminal 64 which is grounded as indicated at 65and the booster relay coil 41 is connected to this terminal as shown. Inall other respects the unit of FIGURE 2 is the same as shown in FIGURE1.

The terminal 55 of the unit is connected by the wire 56 to one side ofthe ignition switch 11, as before, but the second side of the ignitionswitch is connected to ground by a wire '66. The terminal 49 of the unitis connected by a wire 69 with the ammeter 14 and is connected by a wire70 with the fixed contact 23 of the starter relay 18.

When the ignition switch 11 in FIGURE 2 is closed, it completes thefollowing circuit to energize the main relay coil 40 of the unit;positive side of the battery 60, wire 63 to ground; ground to switch 11through wire 66; wire 56, terminal 55 of the unit; coil 40; resistor 54;stationary contact 44; terminal 47; and Wire 48 to the negative side ofthe battery. The resulting energization of the main coil '40 closes themovable contact 43 against the two stationary contacts of the unit andwhen the starter switch 13 is then closed, the following circuit iscompleted to energize the relay coil 20 in the starter relay 18;positive side of the battery 60 to ground through the wire 63; ground tothe relay coil 20 of the starter; wire 26; starter switch 13; wire 32;wire 69; terminal 49; stationary contact 45; movable contact 43;stationary contact 44; terminal 47 and wire 48 to the negative side ofthe battery. The consequent closing of the starter relay 18 conpletesthe following circuit for energizing the booster relay coil 41 in theunit; positive side of the battery 60 to ground through wire 63; groundto terminal 64 of the unit; booster relay coil 41; terminal 57; wire 58;stationary terminal 22 of the starter relay; movable contact 21;stationary contact 45; movable contact 43; stationary contact 44;terminal 47; and wire 48 to the negative side of the battery.

It is apparent in this second wiring arrangement the second form of theunit will operate in substantially the same manner and with the samesequence, of steps as heretofore described.

The third form of the invention shown in FIGURE 3 is incorporated in awiring system which has a battery 70 which is grounded on its negativeside by a wire 71 and on its positive side is connected by a wire 72with the external terminal 47 of the unit. Thus, the unit is interposedbetween the positive side of the battery and the rest of components ofthe automotive wiring system. The unit indicated in FIGURE 3 has asuitable casing 73 which is provided with an external terminal 74connected to ground by a wire 75. In this instance, the unit has onlyone relay coil 80, one side of which is connected to the terminal 74 andthe other side of which is connected through a resistor 81 to theexternal terminal 55 of the unit. In all other respects the arrangementshown in FIGURE 3 is similar to the previously described arrangements asindicated by the use of corresponding numerals to designate identicalparts.

The unit terminal 55 is connected to one side of the ignition switch 11by the usual wire 56 and the other side of the ignition switch isconnected by a wire 82 to the fixed contact 23 of the starter relay 18The external terminal 49 of the unit is connected to the ammeter 14 by awire 76. A wire 77 connects the previously mentioned wire 72 on thepositive side of the battery with the fixed terminal 23 of the starterrelay 18.

When the ignition switch '11 is closed in the arrangement shown inFIGURE 3, the following circuit is completed for energization of therelay coil 80 in the unit; positive side of the battery 70; wire 72;wire 77; wire 82; ignition switch .11; wire 56; terminal 55; resistor81; relay coil 80; terminal 74; wire 75 to ground; and wire 71 fromground to the negative side of the battery. With the relay coil 80energized, closing the starter switch 13 completes the following circuitfor energizing the coil 20 in the starter relay 18; positive side ofbattery 70; wire 72; terminal 47 of the unit; stationary contact 44;movable contact 43; stationary contact 45; terminal 49; wire 76; wire32; starter switch 13; wire 26; relay coil 20; to ground; and wire 71from ground to the negative side of the battery.

In this arrangement, the positive side of the battery 70 is effectivelyisolated from the remaining components of the wiring system aslong asthe ignition switch 11 is open. When the ignition switch is closed,current flows at a minor rate through the relay coil 80 to hold themovable contact 43 in closed position against the resistance of thespring 46. The peak load of current flows only when the starter switch13 is closed but a feature of this arrangement is that it is notnecessary to provide a booster relay coil in the unit for increasing thepressure of the movable contact 43 against the two stationary. contacts44 and 45 because the heavy current is by-passed around the unit by thewire 77.

My description in specific detail of selected specific embodiments ofthe invention willsuggest to those skilled in the art various changes,substitutions, and other departures within the spirit and scope of theappended claims.

I claim:

1. In a battery disconnect circuit for aninternal combustion engine, abattery having a pair of terminals, a pair of conductors for saidterminals, a first relay having a pair of contacts connecting one ofsaid terminals with one of said conductors, an engine ignition switch, aholding coil in said relay in circuit with said battery and said engineignition switch for closing said relay, an engine starter relay,in'series with said contacts ofsaid first relay, and a second holdingcoil in said first relay, connected to be energized when current flowsthrough the starter switch and said energizing coil of said enginestarter relay.

engine ignition switch for closing said relay, a second holding coil insaid relay connected to be energized when current flows through saidfirst relay contacts, and said energizing coil of said engine starterrelay, and a starter switch for operating said engine starter relay,said starter relay being connected with said first relay whereby it isinitially dependent upon said engine ignition switch and said firstholding coil.

3. In a battery disconnect circuit for an internal combustion engine, abattery having a pair of terminals, a pair of conductors for saidterminals, a first relay having a pair of contacts connecting one ofsaid terminals with one of said conductors, an engine ignition switch, aholding coil in said relay in circuit with said battery and said engineignition switch for closing said relay contacts, an engine starterrelay, a second holding coil in said first relay connected to beenergized when current flows through the first relay and said enginestarter relay, and a starter switch for operating said engine starterrelay, said starter relay being connected with said first relay wherebyit is initially dependent upon said engine ignition switch and saidfirst holding coil, said starter relay being in series with said secondholding coil whereby they are both de-energized when said starter switchis open.

4. In a battery disconnect circuit for an internal combustion engine, abattery having a pair of terminals, a pair of conductors for saidterminals, a first relay having a pair of contacts connecting one ofsaid terminals with one of said conductors, an engine ignition switch, aholding coil in said relay in circuit with said battery and said engineignition switch for closing said relay contacts, and an engine starterrelay in series with said first relay, a starter switch for operatingsaid engine starter relay, and a second holding coil in said firstrelay, said starter relay being in series with said second holding coilwhereby they are both de-energized when said starter switch is open.

5. In an apparatus of the character described the com bination of abattery having a pair of terminals, a first relay connected with one ofsaid terminals, a grounded conductor connected with said relay, anengine ignition switch, a holding coil in said relay in circuit withsaid battery and said engine ignition switch for closing said relay, anengine starter relay in series with said first relay, a starter switchfor operating said engine starter relay, and a second holding coil insaid first relay, said starter relay being in series with said holdingcoil whereby they are both de-energized when said starter switch isopen.

6. In an electrical circuit including a battery, an engine starter, anignition switch and a starter switch, the combination therewith of: anormally open ignition relay having a first low'amperage coil and asecond booster coil; and a normally open starter relay in series withsaid ignition relay, battery and starter, said starter relay having acoil, said first coil of the ignition relay being in series with saidbattery and ignition switch, said booster coil being in parallel withsaid starter, said coil of the starter relay being in series with saidstarter, switch, said coil of the starter relay and said starter switchbeing in parallel with said starter and starter relay, whereby closingthe ignition switch closes said ignition relay to make the starterresponsivefto closing of the starter relay and then closing said starterswitch closes the starter relay forenergization of the starter andsimultaneous energization of said booster coil to increase the contactpressure of said ignition relay. 7

7. A unit for installation into the electrical system of an internalcombustion engine and the like, which system 3? includes a source ofelectrical energy, an ignition switch, a starter switch, and a starterrelay including an energizing coil and a pair of normally open contacts;said unit including in combination:' a second relay having a pair ofnormally open contacts; means for connecting said normally open contactsof said second relay in series with the starter switch, the energizingcoil of the starter relay and the source of electrical energy; a coilfor said second relay; means for connecting said main coil in serieswith 8 the source of electrical energy and the ignition switch to causethe normally open contacts of said second relay to be closed in responseto the closure of the ignition switch; a booster coil for said secondrelay; and means for energizing said booster coil in response to theclosure of the starter relay contacts to increase the contact pressureof said normally open contacts of said second relay when the starterrelay is energized.

No references cited.

